Choosing a television

The world of televisions has changed dramatically in the past few years, with slim flat-panel TVs replacing bulky old-style models (known as CRT screen TVs), and digital signals increasingly taking over from analogue.
Alongside some exciting improvements in viewing experience has come a proliferation of technical terms. Shoppers who are looking for a new TV now have to work out whether they want a plasma or an LCD screen, whether they want high definition pictures (HD), whether their screen resolution should be 1080i or 1080p, and whether to plump for HD ready or Full HD.

These terms can be helpful, but are more likely to be confusing unless you know what they mean. In this guide we aim to help you cut a path through this jungle of terms so you can find the TV that is right for you.

Contents

5 Tips for buying a new TV
Digital Switchover
LCD vs Plasma
HD TV
Full HD vs HD Ready
1080i vs 1080p
Connections
Glossary of other terms

5 Tips for buying a new TV

Digital Switchover

Between 2007 and 2012 television signal in the UK will switch over from analogue to digital, one area at a time. Whitehaven in Cumbria was the first to go fully digital in November 2007.

There are a number of immediate advantages to going digital, as well as future-proofing yourself for when your region switches off the analogue signal. Digital signals don’t suffer from interference so you should have a clearer picture. Also, many programmes are broadcast in true widescreen in a digital signal, which is great for watching films (because the image doesn’t have to be ‘squashed’ to fit on the screen).

So what do you need to do in order to receive the new digital signal? There are three ways that you can do this:

1) Buy and connect a digital tuner (also known as a Freeview Box) to your existing television.

2) Get a television with a built-in digital tuner – these are called integrated digital televisions (IDTVs).

3) Cable and satellite providers offer free-to-view and subscription channels. You may need additional equipment for this, usually available directly from the supplier for a one-off payment.

The other big advantage is that you get many more channels, typically around 40.

LCD vs Plasma

If you’re confused about the differences between LCD and plasma screens, we’ve got a simple rule: don’t be. At most screen sizes LCDs are all that is on offer. Its only at large screen sizes (above 37”) that plasma and LCD screens are still battling it out.

If you are looking for a screen that costs below £500 or is smaller than 37”, then LCD is the way to go.

If you are looking for a larger or more expensive set than that, perhaps as the centrepiece of a home cinema set-up, you do need to decide which is right for you. Here is a summary of the advantages and disadvantages of the two technologies.

LCD or liquid crystal displays are probably what you are using to read this page. LCD screens are made up of a grid of pixels, or points. They work by emitting light at each pixel, which acts like a mosaic to build up the overall image.
Advantages:
• generally cheaper at most screen sizes
• longer lasting
• easier to look after
• more energy efficent, and therefore more eco-friendly
Disadvantages:
• slow response time – fast-moving images like sports or action scenes will be blurry
• sometimes black appears lighter on LCD screens than on plasma screens – check the contrast ratio to see which models have this problem.

Plasma screens create images by an electric current causing light to be emitted from gas trapped between two layers of glass.
Advantages:
• fast response time – great for fast-moving images like sports matches
• better contrast ratio than LCD screens
• cheaper than LED
Disadvantages:
• for the screen to be energy-efficent, it has to be quite large (above 37")
• heavier than LCD screens
• generally more expensive than LCD
• some older models suffer from ‘screen burn-in’: when left displaying a static image (like a logo on a 24 hour news channel) for a few hours, pixels would continue to display that image after the channel had been changed. This problem has generally been solved in newer models.

HD TV

HD TV signals (high definition) are now being offered by Sky and Freeview HD will start to be available across the country during 2010, according to the BBC. HD TV gives a better quality picture than standard definition TV (SD TV), sharper and more detailed.

Full HD or HD Ready?

You might have noticed that some TVs are marked as HD Ready and some as Full HD – and occasionally some are marked as both! So, what is HD Ready and what’s the difference between Full HD and HD Ready TVs?

HD ready is a standard used in Europe to make HD technology less confusing. The minimum requirements for a TV to wear an HD ready badge are:
• Minimum vertical resolution of 750 pixels (in widescreen format)
• Ability to display 720p and 1080i formats
• An HDMI or Digital Video Interface (DVI interface)
• It must be compatible with analogue HD sources (like camcorders)

Full HD (or HD 1080p) is a more advanced HD standard, which claims to show HD sources (which are usually in 1080 resolution) to their full potential. TVs bearing this mark must have:
• Minimum 1920×1080 resolution
• Ability to display 1080p format without distortion

Put simply, Full HD gives better picture quality than HD Ready. However, how much difference you will actually see depends on the size of your screen (at 32" or below, the difference is usually undetectable), how good your eyesight is and how close to the TV you sit.

1080i or 1080p?

Although the number at the beginning is the same, 1080p gives a better picture quality than 1080i. The i and p stand for different ways of displaying the pixels: interlaced or progressive. In practical terms, the difference between them is how well fast-moving images are displayed: it tends to be blurry on 1080i screens, but not on 1080p screens. If you want the full details of the differences, head over to our blog post on 1080i and 1080p.

Connections

HDMI Interfaces: These are like a traditional scart interface but capable of carrying HD signals from or to other devices. HDMI inputs connect your digital TV receiver, Playstation 3 or HD DVD player to your TV.

Scart interface: Scart sockets are places where you can connect other devices to your TV. If you already have a (non-HD) DVD player, a VCR and a Playstation you might want to make sure your new TV has enough Scart interfaces so you don’t have to keep crawling round the back of the TV.

Glossary

Contrast ratio: This figure is designed to tell you how much difference there is between dark and light colours on the TV. It is quoted as a ratio, between the brightest white and the darkest black. 500:1 means the brightest white is 500 times more bright than the darkest black. Plasma screens have historically boasted better contrast ratios than LCD screens.

Frequency is how often your TV refreshes the image, units of Hertz (Hz), which simply means number of refreshes per second. A TV with a 50 Hz refresh rate therefore refreshes the screen 50 times per second.

Reflection angle is simply a techy term for viewing angle. It’s designed to express how picture quality performs when it is looked at from an angle. This effect is only an issue for LCD TVs.

Response time is a similar measure to refresh rate. It specifies the time it takes for a pixel to change from being fully black to fully white to fully black again, in milliseconds (ms). A higher response time means a slower performing TV, which means fast moving images are more likely to become blurred.

Screen size in inches: the size of the TV’s screen measured diagonally from corner to corner.

Screen format means the shape of the screen, which is expressed as a ratio between the width and the height of the screen. For example standard format screens (4:3) have the same shape as a 4×3 grid. These are increasingly being replaced by widescreen formats, which have a ratio between the width and the height of the screen of 16:9.

Vertical resolution in pixels: The number of pixels in your TV determines the maximum amount of detail it can display. Because most TVs have hundreds of thousands of pixels, it’s easier to quote the number of pixels across the vertical and horizontal edges. And because most TVs have the same screen shape, it’s simpler still to just quote one of these edges, by convention the vertical one. An HD Ready TV will have a vertical resolution of at least 768 pixels, which gives about 1 million pixels in the screen. a Full HD screen will have 1080 pixel vertical resolution and 2 million pixels in total.

Prepared November 2007
Updated August 2009